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Individual study: Is there a chance for conservation breeding? Ex situ management, reproduction, and early life stages of the harlequin toad Atelopus flavescens Duméril & Bibron, 1841 (Amphibia: Anura: Bufonidae)

Published source details

Gawor A., Rauhaus A., Karbe D., VanDerStraeten K., Lötters S. & Ziegler T. (2012) Is there a chance for conservation breeding? Ex situ management, reproduction, and early life stages of the harlequin toad Atelopus flavescens Duméril & Bibron, 1841 (Amphibia: Anura: Bufonidae). Amphibian & Reptile Conservation, 5, 29-44


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Amphibians: Vary artificial rainfall to simulate seasonal changes in the wild Management of Captive Animals

A replicated, before-and-after study in 2008–2011 in Cologne, Germany found that egg deposition of harlequin toads Atelopus flavescens was stimulated by intensive rainfall following a dry period, whereas none had occurred previously. However, no offspring survived past 142 days. The first three breeding trials with no wet or dry seasons resulted in no egg production. Once a wet and dry season was simulated, two clutches of eggs were produced with 400–500 eggs (5–10% unfertilized). On day 43 after egg deposition, only two larvae survived. One tadpole survived to day 112, the other died as a toadlet at day 142. Males were housed in three groups of 12–15 in tanks (100 x 60 x 60 cm) with artificial streams. Four females were transferred to the tanks for breeding. Tanks were misted several times each day. A dry season with reduced water and misting was then simulated for three months followed by a wet season with increased rainfall using an artificial rain system.

Amphibians: Manipulate temperature of enclosure to improve development or survival to adulthood Management of Captive Animals

A replicated study in 2008–2011 in Cologne, Germany found that the growth rate and development stage reached by harlequin toad Atelopus flavescens larvae was faster at a higher constant temperature rather than a lower and varied water temperature, although no statistical tests were carried out. Tadpoles kept at a steady temperature of 24°C reached development stage (Gosner scale) 41 (which includes increases in length, mouthpart development and disappearance of the tail) in 100 days. Those kept at varying temperatures of 22-24°C took longer to reach the same stage (106-130 days). Delayed metamorphosis may be beneficial or detrimental to survival depending on the relative risk associated with different habitats. The tadpoles were from two reproduction events in December 2010 and January 2011.

Captive breeding harlequin toads (Atelopus species) Amphibian Conservation

A replicated study in 2008–2011 of captive harlequin toads Atelopus flavescens at Cologne Zoo, Germany (Gawor et al. 2012) found that egg deposition was stimulated by maintaining toads in a drier environment followed by a period of intensive irrigation. However, no toadlets survived past day 142. Three breeding trials resulted in no egg production. Following the simulation of a dry then wet season, two clutches of eggs were produced with 400–500 eggs (5–10% unfertilized). On day 43 after egg deposition, only two larvae survived. One tadpole survived to day 112, the other died as a froglet at day 142. Males were housed in three groups of 12–15 in tanks (100 x 60 x 60 cm) with artificial streams. Four females were transferred to the tanks for breeding. Tanks were misted several times each day. A dry season with reduced water and misting was then simulated for three months followed by a wet season with increased water and misting.